Gas without vent for patient interface

Abstract

A gas washout vent, and a patient interface with the gas washout vent, configured to allow patient-exhaled CO2 to flow to an exterior of the plenum chamber to minimise rebreathing of exhaled CO2 by the patient, the gas washout vent including at least one outlet orifice; a diffusing member at least partly covering the outlet orifice; and a blocking member having an air-impermeable material, the blocking member preventing gas exiting from the outlet orifice from flowing straight through the diffusing member.

Description

1 BACKGROUND OF THE TECHNOLOGY1.1 Field of the Technology[0001]The present technology relates to one or more of the detection, diagnosis, treatment, prevention and amelioration of respiratory-related disorders. The present technology also relates to medical devices or apparatus, and their use.1.2 Description of the Related Art1.2.1 Human Respiratory System and its Disorders[0002]The respiratory system of the body facilitates gas exchange. The nose and mouth form the entrance to the airways of a patient.[0003]The airways include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the air into the venous blood and carbon dioxide to move out. The trachea divides into right and left main bronchi, which further divide eventually into terminal bronchioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further div...

AI Technical Summary

Benefits of technology

The present technology is intended to improve the comfort and effectiveness of respiratory therapy for patients with respiratory disorders. One aspect is to provide a gas washout vent with a blocking member that prevents drying of the nasal mucosal tissue and increases patient airway comfort. Another aspect is to provide a patient interface that maintains a therapy pressure in a range of about 4 cmH2O to about -30 cmH2O above ambient air pressure in use, while the patient is sleeping, to ameliorate sleep disordered breathing. The technology also includes the use of a diffusing member and a blocking member with an air-impermeable material to prevent gas from flowing directly through the diffusing member, reducing rebreathing of exhaled CO2. Overall, this technology aims to improve patient compliance with respiratory therapy by increasing comfort and reducing discomfort.

Problems solved by technology

It often causes excessive daytime somnolence, and it may cause cardiovascular disease and brain damage.

It is possible that CSR is harmful because of the repetitive hypoxia.

In some patients CSR is associated with repetitive arousal from sleep, which causes severe sleep disruption, increased sympathetic activity, and increased afterload.

Symptoms include dyspnea, morning headache and excessive daytime sleepiness.

Some NMD patients are characterised by progressive muscular impairment leading to loss of ambulation, being wheelchair-bound, swallowing difficulties, respiratory muscle weakness and, eventually, death from respiratory failure.

Symptoms of respiratory failure in NMD include: increasing generalised weakness, dysphagia, dyspnea on exertion and at rest, fatigue, sleepiness, morning headache, and difficulties with concentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result in inefficient coupling between the respiratory muscles and the thoracic cage.

Scoliosis and / or kyphoscoliosis may cause severe respiratory failure.

Symptoms of respiratory failure include: dyspnea on exertion, peripheral oedema, orthopnea, repeated chest infections, morning headaches, fatigue, poor sleep quality and loss of appetite.

Treatment of OSA by CPAP therapy may be voluntary, and hence patients may elect not to comply with therapy if they find devices used to provide such therapy one or more of: uncomfortable, difficult to use, expensive and aesthetically unappealing.

For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10 cmH2O.

The design of a patient interface presents a number of challenges.

As a consequence of these challenges, some masks suffer from being one or more of obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and uncomfortable especially when worn for long periods of time or when a patient is unfamiliar with a system.

For example, masks designed solely for aviators, masks designed as part of personal protection equipment (e.g. filter masks), SCUBA masks, or for the administration of anaesthetics may be tolerable for their original application, but nevertheless such masks may be undesirably uncomfortable to be worn for extended periods of time, e.g., several hours.

This discomfort may lead to a reduction in patient compliance with therapy.

If a mask is uncomfortable, or difficult to use a patient may not comply with therapy.

Since it is often recommended that a patient regularly wash their mask, if a mask is difficult to clean (e.g., difficult to assemble or disassemble), patients may not clean their mask and this may impact on patient compliance.

A seal-forming portion that may be effective in one region of a patient's face may be inappropriate in another region, e.g., because of the different shape, structure, variability and sensitivity regions of the patient's face.

For example, a seal on swimming goggles that overlays a patient's forehead may not be appropriate to use on a patient's nose.

Furthermore, if the shape of the seal-forming portion does not match that of the patient, it may crease or buckle in use, giving rise to leaks.

Another type of seal-forming portion may comprise a friction-fit element, e.g., for insertion into a naris, however some patients find these uncomfortable.

Some patients may find it inconvenient to constantly apply and remove an adhesive to their face.

However, the use of adhesives may be uncomfortable for some.

Many such harnesses suffer from being one or more of ill-fitting, bulky, uncomfortable and awkward to use.

Many such vents are noisy.

Others may become blocked in use and thus provide insufficient washout.

However, air pressure generators for medical applications have particular requirements not fulfilled by more generalised air pressure generators, such as the reliability, size and weight requirements of medical devices.

In addition, even devices designed for medical treatment may suffer from shortcomings, pertaining to one or more of: comfort, noise, ease of use, efficacy, size, weight, manufacturability, cost, and reliability.

An example of the special requirements of certain RPT devices is acoustic noise.

Delivery of a flow of air without humidification may cause drying of airways.

A range of artificial humidification devices and systems are known, however they may not fulfil the specialised requirements of a medical humidifier.

Room-based systems (e.g. a sauna, an air conditioner, or an evaporative cooler), for example, may also humidify air that is breathed in by the patient, however those systems would also humidify and / or heat the entire room, which may cause discomfort to the occupants.

Furthermore medical humidifiers may have more stringent safety constraints than industrial humidifiers

Some medical humidifiers may provide inadequate humidification, some are difficult or inconvenient to use by patients.

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